This invention relates to surgical cutting guides, and in particular to a guide for a cutting blade in shaping a distal end of a femur to receive a component of a knee prosthesis.
U.S. Pat. No. 6,702,821 to Bonutti, entitled “Instrumentation for minimally invasive joint replacement and methods for using same”, describes a method of performing surgery on a joint in a patient's body using a cutting guide. During cutting of the bone, a surgical cutting guide having guide members with opposite ends spaced apart by a distance less than the width of an implant may be utilized. This patent contemplates making the guide out of inexpensive, light weight material such as polymeric materials.
U.S. Pat. No. 4,721,104 to Kaufman entitled “Femoral Surface Shaping Apparatus for Posterior-stabilized Knee Implants”, describes a surgical cutting guide including (a) a template having (1) a bottom surface which is adapted to be placed in an aligning relationship with the flat surface of a distal femur which has been partially shaped to receive the femoral component of a posterior-stablized knee implant prosthesis and (2) a U-shaped slot passing through the template where the slot is of substantially the same size and shape as the outer periphery of the intercondylar stabilizing housing present on the femoral component to be implanted and (b) a drilling means, preferably in the form of an end-mill cutter, having a stop means thereon and the drilling means closely engages the sides of the U-shaped slot in the template so that the drilling mean can be passed through the U-shaped slot until the stop means contacts a surface of the guide and is then drawn along the slot to create a precisely shaped and aligned recess in the femur for receipt of the intercondylar stabilizing housing. It is contemplated that at least a portion of the guide be made of plastic.
U.S. Pat. No. 6,602,259 to Masini, entitled “Bone cutting guides for use in the implantation of prosthetic joint components” and U.S. Patent application Publication No. 2001001120, also to Masini, entitled “Apparatus and method for preparing box cuts in a distal femur with a cutting guide attached to an intramedullary stem”, describe cutting guides enabling a surgeon to gauge required resection characteristics. It is contemplated to make the guide at least in part from plastic, in particular, polyethylene. In the later mentioned Masini application, the plastic is transparent to enable better visibility of the bone during cutting.
U.S. Pat. No. 5,490,854 to Fisher, entitled “Surgical cutting block and method of use” describes an improved surgical cutting block for guiding bone saws in joint surgery and similar instruments which may also be fabricated from polyethylene plastics.
U.S. Patent Application Publication No. 2006011725 to Biegun, entitled “Accessories for removing bone material and method for making same” concerns a surgical cutting guide in part made of a material harder than the bone material to be cut, as well as plastic material.
U.S. Patent Publication No. 200400260301 to Lionberger, entitled “Cutting guide apparatus and surgical method for use in knee arthroplasty” describes cutting guides and surgical methods for use in knee arthroplasty which are made at least in part by plastic, thus providing for an economical, single-use application.
All of the above references describe guides which include a massive housing which covers the head of the femur and may obstruct view of the bone during cutting. Even the latter Masini device which is transparent may obstruct the view of the bone during cutting when the plastic is covered with body fluids or where refraction of light may distort such view.
An effort to minimize this obstruction is apparent in U.S. Pat. No. 5,817,097 to Howard et al. entitled “Bone Saw with Magnet”. Howard's magnet exerts attractive force in a direction toward the guide body for attracting a bone saw blade or milling instrument to the guiding surface. However, questions may be raised of the secure guiding of the cutting blade when there is no tangible surface to restrict movement of the cutting tool. Further, the strong magnet may have disruptive effects on instruments that are sensitive to magnet fields.
What is needed is a surgical cutting guide for the multiple cuts associated with preparation of the femur for reception of a prosthesis in a manner that minimizes obstruction of the cut surfaces. Further, what is needed is a surgical cutting guide that is light weight, inexpensive and disposable.
Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such material by virtue of prior invention.